Furnace.



G. W. HARRIS & V. O. RITCHAY.

FURNACE.

APPLICATION FILED SEPT. 28, 1915. I 1 ,260,770, Patented Mar. 26,1918.

3 SHEETS-SHEET I.

FII3-2.

G. W. HARRIS V. 0. RITCHAY.

FURNACE. APPLICATION FILED SEPT. 28, 1915.

1,860,770. Patented Mar. 26,1918.

3 SHEETS-SHEET 2- WITNESSES fimwrfsbiy G. W. HARRIS & V. 0. RITCHAY.

FURNACE.

APPLICATION FILED SEPLZB, 1915- 1260370. Patented Mar. 26, 1918.

. 3 SHEETS-SHEET 3.

/6 Fl E- 5 /5 FIE.E.

WlT-NESSES v INVENTPHS v I I I 37 7mm z- @lw see miners Ann naemia: oarr assrenoas, BY eraser AND mean fnrroHAY, ONE-THIRD TO on-name ease, at numerous, same-term, ASSIGNMENTS, ,orjonnnnmn "ro SAID area, are: ONE-THIRD TO anon-ea BRENNEI-SEN, ALL or coaaoeome, eaaasrnvama.

FURnAo'E.

Specification of Letters Patent.

Patented Mar-K26, rare.

Application filed. September 28,1916. serial no. s slo s s.

To all w hom i t may concern:

Be it known that We, GEORGE W. Harr s, and Vin CENT O. RITCHAY, citizens of the United States, residing at .Goraopolis, in the county of Allegheny and State of Pennsylvania, have invented certain nevvand useful Improvements in Fur naceaof which the follovving is a specification. V

The present invention relatesto improvements in furnaces and especially to furnaces adapted to be iused for heating, re-h'eating and annealing purposes as be desired,

The furnace herein disclosed is des gned aore' micuiarly for the treatment of autoquired the use of independent furnacesffor mobile spring leaves, a character of ork requiring careful treatment and involving several steps difi'ering from each other to such an extent that prior practice practically required the use of different furnaces to produce the result.

For instance, the bars are initially heated to a temperature approximating 2000 F., Whereupon, they are removed and shaped; each bar is then re-heated at a temperature approximating 1600 F., then subjected to a tempering bath, after which it is placed in an annealing or drawing furnace for final treatment, the latter being at a heat approximating 900 F. r

Obviously, these relative Wide variations in heat conditions for the several steps render it a difiicult matter to produce the several operations in a single furnace such as that commonly employed for this purpose, owing to the length of time required to bring the furnace to the desired temperature and the greater difliculty in maintaining such temperature approximately uniform. The latter difiiculty is. increased by the fact that in operation, the bars are generally introduced and removed fronrthe furnace individually and hence require thewopening of the heating chambereach time when such change is made, the opening of the chamber permittinginrush of coldair Which tends to vary the temperature, especially at the entrance end of the chamber. 7 7

These difliculties, together With the necessity for completing the seriesofoperations as quickly as possible, have practically redififerent steps, it having been found more economical to employ individual furnaces than to attempt to vary the temperatures of a single furnace in carrying out the several steps. l

The presentinvention is designed With a View to permitting these successive operations to be provided in a single furnace and With greater economy. Inactualpractice involvingan operation covering a series of months, a furnace of thetype disclosed herein has met all of the'conditions required for this particular use. This result is brought about by the faet that the time requiredfor bringing the furnace to its working temperature in the initial step isreduced more than fifty per cent, and when this temperature reachedpit is maintained throughout the period required in completing the fir Which are being treated in the first stage. This ability to rapidly change the temperature of the operating or treating chamber of the furnace then enables thefurnace to be quickly brought to the temperature for the second stage, and, similarly, the temperature can be again quickly changed for the purposes of the third stage. In additiomthe temperature of the treating chamber is maintained substantially uniform, the heating arrangements being such that opening of the chamber is ineffective to materially vary this temperature.

Practical tests of the furnace referred to have'demonstrated that theparticular construction and arrangement of the furnace will permit operation attem ieraturcs ranging frometOO to 3000 F., the temperature being maintained substantially uniform at any desired point Within this range. Furthermore, it has been found that these results are obtainable through the expenditure of a greatly reducedamount of fuel, the furnace referred to operating with the use of approximately one-third to one-half the amount of gas required in other furnaces heretoforeemployed for the purpose, the cost of fuel per ton of material treated being decreased to approximately one-third in the present apparatus.

To these and other ends, the nature of Which Will be readily understood, as the invention ishereinafter disclosed, our invention consists in the improved construction and combination of parts hereinafter fully ststage operation of the bars described, illustrated in the accompanying drawings, and more particularly pointed out in the appended claims.

In the accompanying drawings, in which similar reference characters indicate similar parts in each of the views,

Figure 1 is a front elevation of a denble or twin furnace constructed in accordance I with the present invention.

Fig. 2 is a fragmentary view of the rear of the furnace.

Fig. 3 is a vertical sectional view taken on the line 3-3 of Fig. 1.

particular arrangement of parts disclosed herein being such that it is possible to oper- 7 ate the individual furnaces concurrently at dlfierent temperatures. Obviously, the same general ideas may be employed in a single furnace, the arrangement of fiues being varied in correspondence but retaining the same general characteristics.

10 designates the bottom setting of the furnace, said setting supporting the work- 'ing parts of the furnace. 11 designates the operating or treating chamber which extends from the front toward the rear a suitable distance, said chamber having at its rear a bridge wall 12 which projects above the plane of the bottom of the chamber a suitable distance, said bridge wall forming a contlnuation of a wall 13 of the combustion chamber indicated at 14:, the latter being at the rear of the furnace and having its length equal to the width of chamber 11.

As shown more particularly in Figs. 3, I

a and 6, the upper wall of the combustion wall ofthe furnace. ticularly in Fig. 2, air is admitted into the chamber l-i is formed stepped as indicated at 15, this arrangement not only serving to change the direction of flow of the products of combustiombut also tending to so affect the gases, etc., from the combustion chamber as to better equalize the delivery of the gases, etc., into the chamber 11.

The fuel employed is preferably gas or oil, although other forms of fuel may be employed. Thisis introduced into the combustion chamber through a suitable burner, a preferred form of which is shown in Fig. 7, the burner being indicated generally at 16 and havinga pair of nozzles 17, these nozzles entering suitable ports 18 in the rear As shownmore parcombustion chamber below the nozzle 17 through ports 19, the admixture of air and gas within the combustion chamber being readily obtained, and'through the particular form of walls of the combustion chamber, provision is made for effective combustion, the products being directed into chamber 11 over bridge wall 12, the stepped wall 15 aiding in properly directing these products.

At the front end of chamber 11, the bottom wall of said chamber is formed with a plurality of openings 20, these openings being adjacent to the inletto chamber 11, each opening leading downwardly into a flue 21, the latter extending rearwardly to a point adjacent wall 13 where it connects with a fine 22 leading to the stack, the connection being by lateral passageway 23.

The general arrangement of the fines is best shown in Fig. 5. In this view, each flue 22 is shown as forming the outlet for a pair of fiues 21, this arrangement, in the twin design disclosed herein, providing for the employment of three lines 22 and six lines 21, the nine flues being arranged in sets of three, the lines 22 being located respectively at the center of the furnace and at the opposite sides. As shown more particularly in Fig. 6, this arrangement provides three rearwardly extending fines for each of the two treating chambers, the fines 22 being located in the walls of the furnace between the two chambers and on the outer sides of such chambers.

As a result, we not only provide for heating the bottom wall or floor of chamber 11 from beneath, .but also practically insure that the products employed for this purpose are of substantially uniform temperature, this being due to the fact that each of the three flues which provide this heating action are of similar length and have the gases traversing them in the same direction. As shown more particularly in Fig. 4, the front enclsof flues 22 lead into flues 24: which extend to the stack 25.

The flues 21 extend to the front wall of the furnace, and may be permanently closed in advance of open-ing 20, but we prefer to close these advance ends through the use of loose bricks2l which are not only readily removed for cleaning purposes, but which, in addition, may provide a small leakage of air into the fines.

Each treating chamber is closed by a door 26, these doors being preferably arranged to be slidable vertically and operable by the foot of the furnace operator, this result being obtained by the use of a pivoted lever 27 carrying a member 28 which is connected to the door 26 by a suitable connection, in

dicated as a wire rope 29. ,The opposite end.

of lever 27 is connected to a treadle 30 by suitable connection 31, the arrangement bemg such that when the opera-tor places his foot on treadle 30,-lever 27 will be rocked to raise door 26, said door returning to its closing position by its weight when treadle is releasedby the operator. A suitable counterpoise 32 may be employed on the lever 27 to permit easier manipulation of the d00' 2-6 by the operator-who, at this time, is also expected to be engaged in mampulatmg the contents of the treating chamber 11.

are initially led into the treating chamber 7 11-, being directed thereinto ov'er bridge wall ;ough combustion of the mixture. tion is such that, for certain purposes, it may 12 and toward the top of said chamber, these gases then traversing the chamber-to the front end of the latter where they pass dewmvardly through openings 20 into fiues 21, the latter leading the. gases rearwardly under the chamber bottom to the rear end of the chamber, where the gases are then passed to fines 22- cm routeto the stack 25. Wl ile'the gases are thus broughtdirectly into the treating'chamber 11, the bridge wall 12 acts to prevent the flame, etc., from sweeping the fioor of this chamber, thereby providing a space or zone immediately above the floor which, while directlyopen to the remainder of the chamber, is substantially free from the direct passage of the gases therethrough, the gases traversing the top of chamber 11 and thus providing a heat radiation effect on the bottom of the chamber throughoutthe length of travel of the gases within the chamber 11. Consequently, this zone is substantially immune from liability of direct contact of flame and the contents of the zone, so that articles which may be placed within this zone below the top plane of the bridge wall are practically immune from damage by flame contact. As heretofore pointed out, furnace constructed in accordance with the present invention has been in constant service for a number of months, and during this period, practically no loss has been hadthrough damage in this form although the particular character of the work operated'upon is such as to necessitate close inspection for such damage.

' carry the mixture into contact with the'porlion 15 in. a manner to provide a more thor- This acbe possible to omitthebridge wall. 12 and still form the zone heretofore referred to,

since the direction of flow of the gases forced by this inclined wall would tend to carry them to the top of the treating chamber and form results from flame contact. However, We prefer for general operationand especially for the particular use heretofore pointed out, to employ the bridge wall structure referred to,- the i11- clination of wall 13 having a similar effect where the bridge wall. is employed.

his will be readily understood, the ability to employ the heat direct from the gases themselves, in addition to theheat radiation which may be provided by the top walls of the chambers not only provides for rapid heating of the chamber, but also places this heat insuch manner that it tends to prevent the entrance of cold air into the chamber when the door 26 is opened to change the contents, a comparatively short period due This result is due to the fact that the heated gases must traverse the chamber to its front in seeking the outlets for the gases. Should there be any tendency of the colder air to enter when the door is opened, the fact that openings 20 are adjacent the door would tend to cause any cold air which might enter to be carried into the fines 21 instead of into chamber 11.

It will be obvious, therefore, that with the material being treated located within this open Zone at the bottom of the chamber 11, such material will be subjected to the direct action of the ieated gases passing through the chamber above the material as well as of the radiant heat from the top of the chamber, and at the same time is subjected to the action of the heat of the wall which supports this material and which is maintained heated by the passage of the gases through the lines 21, thus producing union the material. In addition, this particular arrangement enables the chamber to be quickly heated to the desired temperature, after which the temperature is maintained by reason of the ineffectiveness of any entering air to materially change this condition.

Obviously, variations in temperature are readily obtainable by the use of a controllable burner. A preferred form of burner,

where gas is the fuel employed, is illustrated in Fig. 7, in which 35 represents the gas inlet leading to an elbow 36 to which is connected a perforated pipe 37 having its free end closed, the elbow 38 and pipe 37 being preferably located within a tube 38, one end of which is connected to an air inlet 39, the opposite end being connected to a tubular arm 40 to which the nozzles 17 are connected. The tubular pipe 38 thus becomes a mixing chamber for the gas and air, the gas emerging from the perforations of pipe 37 at direct right angles to the direction. of travel of the air entering through inlet 39, the result being that a maximum admixture of air and gas ishad within thistube, which mixture is then led to the nozzles and into the combustion chamber, the latter being supplied with its air for supporting combusi tion through air inlets 19. Through the varione controls of the gas and the air inlet 39, it will be readily understood that any desired admixture of air and gas may be provided, in addition to which, the air inlet opening 19 may be controlled through the use of suitable means such as removable bricks, etc., for regulating the amount of air admitted to support combustion within the combustion chamber. Where high temperatures are desired, the air inlet 39 may be connected to a blast, and thus increase the effeet, the addition of a blast being a wellknown practice in this art.

, It is to be understood, of course, that each chamber has its individual burner and control, so that while one chamber may be operating ataone temperature, the other chamber may be operating at an entirely different temperature, each having its temperature maintained substantially uniform to perform the particular character of work intended. 7

It will be obvious that the same general principles may be employed in connection with a furnace having but a single chamber, or thestructure may be amplified to increase the number of chambers, it being necessaryonly to properly arrange the tines 21 and 22 to produce these results, this arrangement being along the lines indicated in Fig. 5.

While the present invention is more particularly adapted for use in the connection heretofore referred to, it is obvious that it may also be employed in connection with other uses, such for instance as the treatment of cutlery, hardware, etc., the bridge wall having its height determined by the character of the work which the furnace is designed to perform.

\Vhile we have herein shown and described a preferred way in which the invention may be carried into effect, it is obvious that changes and modifications therein may be required or desired to meet particular conditions incident to particular uses, and we desire to be understood as reserving the right to make any and all such changes and modifications as may be found necessary in so far as the same may fall within the spirit and scope of the invention as expressed in the accompanying claims.

What we claim is :V

1. In a furnace of the character described, a chamber for the material to be treated, a combustion chamber in open communication with the treating chamber, means between said chambers for producin a zone within the treating chamber substantially immune to direct flame contact of the furnace gases, said zone being adapted to receive the material being treated, an up-take for the furnace gases, and an elf-take between the treating chamber and the uptake, said off-take including parallel flues ositioned below the plane of the hearth of the treating chamber, said flues being arranged in sets divided from-each other, each set having heating fines and a return flue, said heating flues having individual connection with the treating chamber, said return flue being connected to the up-take and the remaining lines of the set.

2. In a furnace of the character described, a chamber for the material to be treated, a combustion chamber in open communication with the treating chamber, means between said chambers for producing a zone within the treating chamber substantially immune to direct flame contactof the furnace gases, said zone being adapted to receivethe material being treated, an up-take for the furnace gases, and an off-take between the treating chamber and the up-take, said off-take ineluding parallel flues positionedbelow the plane of the hearth of the treating chamber, said flues'being arranged in sets divided from each other, each set having a pair of heating flues and a return flue, said heating fines having individual connection with the treating chamber, said return flue being eonneeted to the up-take and the remaining fines of the set.

3. In a furnace of the character described,

a chamber for the material to be treated, a combustlon chamber in open communlcation with the treating chamber, a bridge wall between said chambers for producing a zone within the treating chamber substantially immune to direct flame contact of the furnace gases, said zone being adapted to receive the material being treated, an up-take for the furnace gases, and an elf-take be tween the treating chamber and'the up-take, said off-take including parallel flues positioned below the plane of the hearth of the treating chamber, said fines being arranged in sets divided from each other, each set hav- 'immune to direct flame contact of the furnace gases, said zone being adapted to receive the material being treated, an up-take for the furnace gases, and an off-take between the treating chamber and the up-take, said off-take including parallel lines positioned below the plane of the hearth of the treating chamber, said fines being arranged in sets divided from each other, each set havchamber, an Lip-take for the furnace gases,

nee -#70 ing a pair ofheating fiues and-a return flue, said. heating fines having individual connection with the treating chamber, said return flue being connected tothe up' take and the 'remaining'flues of the set.

between said chambers to restrict the path of the furnace gases within the treating and an off-take between the treating chambar and the tip-take, said-ofi t'ake including parallel fiues positioned-below the plane of the" hearth of the treating chamber, said fiues being arranged in sets divided from each other, each sethaving heatingflues extending a distance substantially equal to the length of the treatingchamber, and a return flue, said heating flues having individual connections with thetr'eating, chamber, said return flue being connectedto the uptake and the remaining flues of the set.

6 In a furnaceof the'character described, a treating chamber having an inlet atone end, a combustion chamber located at the opposite end of and in open communication with the treating chamber, a bridge wall between said chambers to restrict the path of the furnace gases within the treating chamher, said bridge wall having a projecting height less than half the distance between the hearth and roof of the treating chamber, an Lip-take for the furnace gases, and an off-take between the treating chamber and the up-take, said off-take including parallel flues positioned below the plane of the hearth of the treating chamber, said flues being arranged in sets divided from each other, each set having heating fiues of equal length and a return flue, said heating fiues having individual connection with the treating chamber, said return flue being connected to the up-take and the remaining fines of the set.

7. In a furnace of the character described, a treating chamber having an inlet at one end, a combustion chamber located at'the opposite end of and in open communication with the treating chamber, a bridge wall between said chambers to restrict the path of the furnace gases within the: treating chamber, and an off-take for the furnace gases, said off-take being open'through the.

bottom of the treating chamber adjacent the inlet to the latter, said off-take including a plurality of fines of equal length located below the floor and extending in the direction of length of the treating chamber, said flues having independent inlets and a common outlet. i

8. In a furnace of the character described, a pair of treating chambers each having a combustion chamber individual to and in opeircommunication with itself, a bridge Wall between each treating chamber and its combustion chamber, and off-take means for the furnace gases, said means leading from the treating chambers and including fines arranged in independent sets, greater in number than the numberof treating chambers,-one ofsaid sets being operative in connection with both chamber 9; Ina furnace ofthe'character described, a pair of treating; chambers each having a combustion cliunber individual .to and n open communication with its'e1f,]a bridge wall between each treating chamber and its combustion chamber, and off-take means for the furnace gases, said means leading from the treating chambers. said means including a set of fines for and leading from each treating chamber and adapted to heat the floor of such chamber and a third set leading from both chambers and aidingthe remaining sets in the heating operatiomeach set opening to a pair of fines forming'an oiltake for the gases from the heating flues.

10; In a furnace of the character'- de scribed, a pair of treating chambers each having a combustion chamber individual to and in open communication with itself, a bridge wall between each treating chamber and its combustion chamber, and off-takc set leading from both chambers and aiding the remaining sets in the heating operation, each set having an independent off-take flue. 11. In a furnace of the character described, a pair of treating chambers each having a combustion chamber individual to and in open communication with itself, a bridge wall between each treating chamber and its combustion chamber, and off-take means for the furnace gases, said means leading from the treating chambers, said means including a set of fines for and leading from each treating chamber and adapted to heat the floor of such chamber and a third set leading from both chambers and aiding the remaining sets in the heating operation,

divided from each other, each set having heating fines and a return flue, a heating flue of one set being operative with respect to the treating chamber heated by the heating fines of another set.

13. In a furnace of the character described, a pair of treating chambers each having a combustion chamber individual to and in open communication with itself, a

bridge wall between each treating chamber and its combustion chamber, said bridge .wall having a projecting height. less than half the distance between the hearth and roof of the treating chamber, and off-take means for the furnace gases, said means comprising a plurality of flues located below the plane of the hearth of the treating chambers, said fines being arranged in sets divided from each other, each set having heating fines and a return flue, a heating flue of one set being operative with respect to the treating chamber heated by the heating lines of another set.

14. In a furnace of the character described, a pair of treating chambers each 2 having a combustion chamber individual to and in open communication with itself, a bridge wall between each treating chamber and its combustion chamber, and off-take means for the furnace gases, said means com prising a plurality of fines located below the plane of the hearth of the treating chambers, said flues being arranged in sets divided from each other, each set having heating fiues and a return flue, the flues on op- 8 posite sides of the division between sets operating in connection with the same treating chamber.

Intestimony whereof, we aflix our signatures inpresence of two witnesses.

GEORGE W. HARRIS. Witnesses:

DON T. GLEAsoN, ALEX. S. MABON.

VINCENT O. RITCHAY. Vitnesses:

JOSEPH L. MoALms'rnR, THEODOR WIEDERMANN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. e 

